35 ILCS 200/6-35
In counties with 150,000 or more and less than 3,000,000 inhabitants which had an elected board of review on January 1, 1993, the board of three persons shall continue in office. Every two years, at the regular election of county officers in such counties, one member of the board of review shall be elected to succeed the member whose term expires in that year. Each member shall hold office for a term of 6 years and until a successor is elected and qualified. The persons so elected shall qualify within 10 days after the canvass of the vote is completed. They shall hold no other lucrative public office or public employment. Each member shall receive an annual salary to be fixed by the county board and paid out of the county treasury. In case of any vacancy in the board of review or the failure of any person elected to that office to qualify, the vacancy shall be filled by appointment as provided in the general election law until a successor is elected and has qualified. The member having the shortest term to serve shall be the chairman of the board.
35 ILCS 200/6-35